1. Field Of The Invention
Cold packing and pressure bandages are both well known medical management techniques. Cold packing is particularly well suited to the treatment of bruises, muscle strains, sprains and similar muscle, ligament and joint dysfunctions while pressure bandages and splints are used to control hemorrhage, temporarily secure pressure and antiseptic compresses while inhibiting the contamination of the injured surface by airborn bacteria and the like.
More conventional cold packing methods like ice bags, wet cloths, etc., can provide only short periods of relief for a number of reasons. Ice packs have to be periodically recharged requiring personnel time and the expense of purchase, transport, storage and replacement of large quantities of ice. Also, ice bags and wet cold cloths create a very damp cold which, while more tissue penetrating than dry cold is usually a more painful procedure to the patient than dry cold. These treatments also tend to dampen the surrounding area which has obvious contraindications in a sterile field or surgical theater. Additionally, recent medical advances in cryogenics and cryotherapy have indicated that lower temperatures than the operational range of ice packs and baths, usually 35.degree. F. or so, are needed in some comprehensive medical management regimens. Along with these findings have come the need to produce ultracold methodology instrumentation. Additionally, these ultracold treatments have been seen to be less painful to the patient than damp cold treatments.
Concomitant advances in medical pressure usage techniques have disclosed the usefulness of intermittent variation in the pressure applied to a treated area. Traditionally, pressure bandages and splints have been of extremely simple design and usually able only to exert one fixed pressure. Any desired change in pressure was manually adjusted. Such adjusted pressures cannot be established accurately with ordinary procedures. While this technique of manual pressure variation is acceptable for crisis treatments, like acute cardiopulmonary or cardiothorasic events, the continued rotation and adjustment of pressure bandages and the like is not suited to routine treatment of subacute conditions since it would require the continuous presence of trained medical personnel.
Recently, chemical cold packs have been introduced. These devices are simply two or more chemical solutions or substances stored separately in a packet. Upon need an internal seal is broken, the substance mix and the reaction produces a strongly endothermic reaction thereby cooling the cold pack to a single, preset at the manufacture point, low temperature. The devices are typically used in remote site use, like a paramedical team, and suffer also from some serious disadvantages in general use. First, these packs are extraordinarily expensive, have only a one use lifetime, have a single nonadjustable temperature and exert cold only for a short period of time.